Theory and practice of reversing control on multiply-articulated vehicles

A path-tracking controller is presented for automating the reversing of multiply-articulated vehicles. This uses a state feedback approach and steers the wheels of the front axle to ensure that the rearmost vehicle unit tracks a specified path. Linear closed-loop analysis is performed and shows that the controller is stable for vehicles with up to six trailers. The controller is implemented on three full-size experimental heavy vehicles: a ‘tractor–semitrailer’, a ‘B-double’ vehicle and a ‘B-triple’ vehicle, which have one trailer, two trailers and three trailers respectively. Experimental results are presented and the controller performance is evaluated. All test vehicles were able to track the paths to within 400 mm of the desired path. This research was funded by the Engineering and Physical Sciences Research Council (EPSRC) and Volvo Trucks through an Industrial CASE award. The authors would like to acknowledge Leo Laine and Carl-Johan Hoel from Volvo Trucks for their collaboration and contributions to the research.This is the author accepted manuscript. The final version is available from Sage via http://dx.doi.org/10.1177/095440701559691

Path-tracking of a tractor-trailer vehicle along rectilinear and circular paths: A Lyapunov-based approach

Published versio

Driver's field of view from large vehicles: phase 4 - final report.

Driver's field of view from large vehicles: phase 4 - final report

BACKWARD MOTION PLANNING AND CONTROL OF MULTIPLE MOBILE ROBOTS MOVING IN TIGHTLY COUPLED FORMATIONS

This work addresses the development of a distributed switching control strategy to drive the group of mobile robots in both backward and forward motion in a tightly coupled geometric pattern, as a solution for the deadlock situation that arises while navigating the unknown environment. A generalized closed-loop tracking controller considering the leader referenced model is used for the robots to remain in the formation while navigating the environment. A tracking controller using the simple geometric approach and the Instantaneous Centre of Radius (ICR), to drive the robot in the backward motion during deadlock situation is developed and presented. State-Based Modelling is used to model the behaviors/motion states of the proposed approach in MATLAB/STATEFLOW environment. Simulation studies are carried out to test the performance and error dynamics of the proposed approach combining the formation, navigation, and backward motion of the robots in all geometric patterns of formation, and the results are discussed

A numerical control algorithm for a B-double truck-trailer with steerable trailer wheels and active hitch angles. Part 2: reversing

The authors have previously proposed a solution to the twin problems of wheel scuffing and off-tracking of B-double truck–trailer vehicles thereby reducing tyre wear and environmental damage as well as improving maneuverability. The solution to the scuffing problem requires that trailer axles in excess of one per trailer must have steerable wheels. However, if all trailer wheels are steerable, then the off-tracking problem can also be solved. The previous work devised an algorithm for a B-double in forward motion, whereby an on-board computer would be used to calculate the correct wheel and hitch angles and a control system would implement these angles. The purpose of the present technical note is to complete the study of a numerical algorithm for navigating a B-double truck–trailer vehicle by considering travel in the reverse direction. In this case the angle of the front wheels of the truck must also be controlled by the on-board computer. The algorithm for determining the effective angle of the truck’s steerable wheels is derived using an innovative combination of vector geometry and calculus and completes the total control system for these B-double vehicles. The paper concludes with a simulation study of the control algorithm demonstrating its versatility for reversing along twisting paths and effectiveness in reducing off-tracking

Western Home Transport v. Dept. of Labor Amicus Brief Dckt. 40462

https://digitalcommons.law.uidaho.edu/idaho_supreme_court_record_briefs/1860/thumbnail.jp

Path-tracking control for a tractor-trailer via input-output linearization

Vehicle's model -- Path tracking dynamics -- Path tracking control design -- An application example

Trends in vehicle motion control for automated driving on public roads

In this paper, we describe how vehicle systems and the vehicle motion control are affected by automated driving on public roads. We describe the redundancy needed for a road vehicle to meet certain safety goals. The concept of system safety as well as system solutions to fault tolerant actuation of steering and braking and the associated fault tolerant power supply is described. Notably restriction of the operational domain in case of reduced capability of the driving automation system is discussed. Further we consider path tracking, state estimation of vehicle motion control required for automated driving as well as an example of a minimum risk manoeuver and redundant steering by means of differential braking. The steering by differential braking could offer heterogeneous or dissimilar redundancy that complements the redundancy of described fault tolerant steering systems for driving automation equipped vehicles. Finally, the important topic of verification of driving automation systems is addressed

Vision-based trailer pose estimation for articulated vehicles

Articulated Heavy Goods Vehicles (HGVs) are more efficient than conventional rigid lorries, but exhibit reduced low-speed manoeuvrability and high-speed stability. Technologies such as autonomous reversing and path-following trailer steering can mitigate this, but practical limitations of the available sensing technologies restrict their commercialisation potential. This dissertation describes the development of practical vision-based articulation angle and trailer off-tracking sensing for HGVs. Chapter 1 provides a background and literature review, covering important vehicle technologies, existing commercial and experimental sensors for articulation angle and off-tracking measurement, and relevant vision-based technologies. This is followed by an introduction to pertinent computer vision theory and terminology in Chapter 2. Chapter 3 describes the development and simulation-based assessment of an articulation angle sensing concept. It utilises a rear-facing camera mounted behind the truck or tractor, and one of two proposed image processing methods: template-matching and Parallel Tracking and Mapping (PTAM). The PTAM-based method was shown to be the more accurate and versatile method in full-scale vehicle tests. RMS measurement errors of 0.4-1.6$^\circ$ were observed in tests on a tractor semi-trailer (Chapter 4), and 0.8-2.4$^\circ$ in tests on a Nordic combination with two articulation points (Chapter 5). The system requires no truck-trailer communication links or artificial markers, and is compatible with multiple trailer shapes, but was found to have increasing errors at higher articulation angles. Chapter 6 describes the development and simulation-based assessment of a trailer off-tracking sensing concept, which utilises a trailer-mounted stereo camera pair and visual odometry. The concept was evaluated in full-scale tests on a tractor semi-trailer combination in which camera location and stereo baseline were varied, presented in Chapter 7. RMS measurement errors of 0.11-0.13 m were obtained in some tests, but a sensitivity to camera alignment was discovered in others which negatively affected results. A very stiff stereo camera mount with a sub-0.5 m baseline is suggested for future experiments. A summary of the main conclusions, a review of the objectives, and recommendations for future work are given in Chapter 8. Recommendations include further refinement of both sensors, an investigation into lighting sensitivity, and alternative applications of the sensors.This work was supported by a "CSIR South Africa Cambridge Scholarship", funded jointly by the Cambridge Commonwealth, European & International Trust and the Council for Scientific & Industrial Research (CSIR South Africa)

A tool for defining models of generic mobile machines

Tässä työssä esitellään mielivaltaisten liikkuvien työkoneiden nopeaan ja helppoon määrittelyyn tarkoitettu ohjelmisto. Käyttäjä määrittelee työkoneen yksinkertaisen, intuitiivisen 3D-käyttöliittymän avulla. Työkoneen määritelmän perusteella generoidaan sen kinemaattinen malli. Kinemaattisissa laskuissa käytetään uusimpia tutkimustuloksia erilaisten ajoneuvojen kinematiikasta. Generoiduilla kinemaattisilla malleilla voidaan simuloida mielivaltaisia konekonfiguraatioita erillisessä simulaattorimoduulissa, joka luotiin osana tätä työtä. Simulaattori tukee yleisimpiä teollisuudessa käytettyjä liikkuvia konetyyppejä, kuten automaisia, telaketjullisia, runkonivellettyjä tai passiivisesti yhdistettyjä koneita. Simuloidut ajoneuvot voivat myös yhdistellä eri konetyyppejä. Ohjelmistolla generoiduilla kinemaattisilla malleilla simuloidaan erilaisia tosimaailman ajoneuvokonfiguraatioita. Simulaatiotuloksia verrataan oikeista koneista saatuun dataan. Mallien havaitaan olevan tarkkoja ja sopivia erilaisiin tarkoituksiin, jotka vaativat ajoneuvon kinemaattisen mallin.In this thesis work, a software tool for quickly and easily defining a mobile vehicle is presented. Vehicles are defined through a simple, intuitive 3D graphical user interface. Based on the vehicle definition, a kinematic model is generated for the vehicle. The kinematics calculations use state-of-the-art knowledge on the kinematics of different vehicle types. The generated kinematic models can be used in a separate simulator module, also created for this thesis work, to simulate arbitrary vehicle configurations. Supported vehicle types include the most common mobile industrial vehicles, such as car-like, tracked, center-articulated or passively linked vehicles. Simulated vehicles can also be combinations of these types. Kinematic models generated with this software are tested against data sets gained from different real-world vehicle configurations. The models are found to be accurate and suitable for various purposes requiring a kinematic model of a vehicle